The invention generally relates to a pitter for pitting drupes, such as clingstone peaches, apricots, or the like. More specifically, the invention relates to an improved mechanical blade assembly for a selective drupe pitter particularly adapted for pitting clingstone peaches.
Various mechanical drupe pitting devices have been developed for selectively responding to the wide range of drupe conditions. With many drupes, specifically with clingstone peaches, different methods of pitting are used depending upon the condition of the pit. When the peach has a sound pit, pitting may be accomplished using a "torque" type pitter. Such a device bisects the flesh of the peach using a pair of generally opposing blades converging upon the pit. When the blades reach the pit, the pit is gripped at its opposite sides and the peach halves are twisted or torqued in opposite directions by adjacent jaws to separate the peach halves from the held pit. The pitted halves and the pits then drop out of the assembly and a new peach is introduced to begin the cycle anew.
When the peach pit is unsound, for example a split, cracked or otherwise damaged pit, conventional torque-type pitting assemblies are ineffective because the blades will travel through the pit rather than gripping it as required for torque-type separation from the peach halves. As a result, when a pit is unsound the blades can often bisect the entire peach including the pit. Obviously, this result is unsatisfactory. Spoon pitting techniques are employed when the particular pit is unsound. Spoon pitting uses a curved blade normally confined within the plane of one of the peach bisecting blades to spoon out the unsound pit and thereby separate the pit from the peach flesh. Until recently, torque-type pitting and spoon pitting were accomplished using separate devices which significantly decreased pitting efficiency.
Advanced devices have been developed which allow selective torque-type pitting and spoon pitting using the same device. Such a device is disclosed in U.S. Pat. No. 4,158,993 issued Jun. 26, 1979. This type of selective peach pitter automatically torque-pits clingstone peaches having sound pits, spoon-pits clingstone peaches having split or defective pits and bisects clingstone peaches having "late" split pits without requiring modification to the device or interrupting the pitting cycle.
Selective pitting devices conventionally suffer from high maintenance requirements due to the large number of moving parts and rapid operating speeds. Blade assemblies for selective pitting devices particularly suffer from gradual wear in the linkage operating the movement of the upper and lower blades. Excessive wear leads to play in the operational linkage causing loss of grip on the peach pit reduction of pitting efficiency, and ultimately incomplete pit removal from the peach. Existing blade assemblies employ numerous pivot points, each having bushings or bearings prone to excessive wear and corrosion when subject to inadequate lubrication. It is not uncommon for selective peach pitting devices to operate at machine speeds of 60 to 75 cycles per minute. At this operation speed and during long operating cycles, the device must be closely monitored for wear and preventative maintenance. For typical maintenance, replacement and relubrication, the entire blade assembly must be removed from the machine for in-season repair of bearings, cam followers, springs, etc. Annual after-season overhauls also require removal of the blade assembly from the machine for replacement of worn out parts and sharpening, etc.
It is highly desirable, therefore, to minimize wear of blade assemblies in an effort to reduce or eliminate in-season maintenance and replacement and minimize time and expense required for after-season overhaul without compromising pitter production and capacity.